import Foundation
import ObjectiveC
import Tiercel

// extension DownloadTask {
//     private static var PREVIEW_IMAGE_KEY: Void?

//     var previewImageUrl: String? {
//         get {
//             objc_getAssociatedObject(self, &Self.PREVIEW_IMAGE_KEY) as? String
//         }
//         set {
//             objc_setAssociatedObject(self, &Self.PREVIEW_IMAGE_KEY, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
//         }
//     }
// }
